This invention relates to a grinding machine for grinding saw chain, and more particularly to a grinding machine for grinding the cutters that form a part of cutter links in a saw chain and that produce the cutting action when a saw chain moves through wood.
The usual cutter link in conventional saw chain includes what is referred to herein as a body portion forming the base of the link, which receives the rivets connecting the cutter link to other links in the chain. Projecting upwardly from this body portion at the forward end of the link is a depth gauge. Disposed rearwardly of this depth gauge, and separated from the depth gauge by a gullet, is the cutter of the cutter link, which includes a side flange portion projecting upwardly form the body portion of the link and joining with this side flange portion a top plate or toe portion. In so-called chisel chain the top plate and side flange join at a sharp angle, whereas in so-called chipper chain the joinder is not at a sharp angle but over a curved round. The leading portion of the cutter, be it chipper or chisel type chain, including the top plate and its side flange portion, is ground to have a sharp cutting edge, and it is this cutting edge which produces the cutting action when the saw chain is pulled through wood.
It is important in precisely grinding cutters in cutter links that the cutter link which includes the cutter be precisely and firmly held with movement of a cutter against a grinding surface to produce the sharpening action. A general object of this invention is to provide an improved system for supporting a cutter link and holding it in place during the grinding a cutter link and holding it in place during the grinding operation.
Another object is to provide an improved system or means for holding a cutter link during its grinding which is readily released to permit successive cutters to be moved into what is referred to herein as a pre-grinding position in the grinding machine, and which is then actuatable quickly to hold firmly the cutter link on a support for the link and move the link so that its cutter advances into a grinding surface of a grinding wheel.
In a conventional cutter link, the cutter which extends in a new link typically form approximately midway between the ends of the link to the rear of the link, slopes downwardly progressing toward the rear end of the cutter. As a consequence, with older chain, where the length of the cutter has been reduced by reason of repeated grindings for sharpening purposes, proper grinding of a cutter occurs with the edge of the grinding wheel which produces the grinding extending farther into the gullet of the cutter link and toward the body of the link than is the case with the grinding of new chain. In grinding machines it is possible to make adjustments whereby with a cutter link having a relatively short cutter the grinding wheel may be positioned to extend farther into the link. However, there are obvious advantages in a machine where the penetration of the grinding wheel edge into the cutter link adjusts automatically, with a deeper penetration occurring with the grinding of cutter links having relatively short cutters than occurs with cutter links having long or relatively new cutters. An object of this invention, therefore, is to provide in a grinding machine a construction which produces this type of adjustment automatically.
Another object of this invention is to provide a grinding machine with improved means for supporting and moving a cutter link from a pre-grinding position to advance the cutter of the link against the margin of a grinding wheel. The structure contemplated in a preferred embodiment of the invention includes a support for a cutter link, a pivot mounting for the support whereby it moves in an arc carrying any link held thereon upwardly and against the margin of a protruding grinding wheel, and a cam-acting positioner engageable with the top and rear of the cutter in the link which operates to hold the link firmly in place and through movement of the positioner to produce movement of the link whereby its cutter moves against the margin of a grinding wheel.
These and other objects and advantages are obtained by the invention, which is described below in conjunction with the accompanying drawings, wherein: